45378

Colonoscopy, flexible, diagnostic, including collection of specimens by brushing or washing, when performed.

CPT code 45378 describes a flexible diagnostic colonoscopy, which involves the visual examination of the entire large intestine (colon and rectum) using a long, flexible, lighted tube with a camera (colonoscope). The procedure begins with the insertion of the colonoscope through the anus and its advancement through the rectum, sigmoid colon, descending colon, transverse colon, ascending colon, and into the cecum (the beginning of the large intestine), ideally reaching the ileocecal valve. This allows for direct visualization of the mucosal lining of the colon to identify abnormalities such as inflammation, ulcers, polyps, strictures, or sources of bleeding. The code includes the collection of specimens by brushing or washing, when performed, for cytological or histological examination, but it does not include therapeutic interventions such as polypectomy (which would be coded separately with a more specific therapeutic colonoscopy code). This procedure is primarily diagnostic in nature.

Clinical Indications

  • Evaluation of symptoms such as unexplained rectal bleeding, hematochezia, melena, or positive fecal occult blood test (FOBT) or fecal immunochemical test (FIT).
  • Investigation of chronic or unexplained abdominal pain, changes in bowel habits (e.g., chronic diarrhea or constipation), or unexplained iron deficiency anemia.
  • Screening for colorectal cancer in average-risk individuals at age 45 (or earlier for high-risk individuals), when no polyps are found or when a lesion is found and only biopsied (not removed during the same session).
  • Surveillance for individuals with a history of colorectal polyps or cancer, inflammatory bowel disease (Crohn's disease, ulcerative colitis), or certain genetic syndromes.
  • Follow-up for abnormal findings on other imaging studies of the colon (e.g., CT colonography, barium enema).
  • Assessment of known inflammatory bowel disease activity or complications.
  • Unexplained weight loss or other systemic symptoms suggestive of gastrointestinal pathology.

Procedure Steps

  1. Patient preparation, including thorough bowel cleansing, and administration of conscious sedation or general anesthesia.
  2. Patient positioned appropriately (typically left lateral decubitus).
  3. Digital rectal examination performed to assess the anal canal and rectum and facilitate colonoscope insertion.
  4. Insertion of the lubricated colonoscope through the anus into the rectum.
  5. Careful advancement of the colonoscope through the sigmoid colon, descending colon, transverse colon, ascending colon, and into the cecum, often with air or CO2 insufflation to distend the lumen for optimal visualization.
  6. Thorough examination of the entire colonic mucosa during withdrawal of the colonoscope.
  7. Identification and detailed documentation of any abnormalities, including their location, size, and characteristics.
  8. Collection of tissue specimens (biopsies) from suspicious lesions, inflamed areas, or for surveillance purposes, using endoscopic forceps or brushes, if indicated.
  9. Removal of the colonoscope and post-procedure monitoring of the patient until stable.

Coding Guidelines

  • When a diagnostic colonoscopy (45378) identifies a lesion requiring a therapeutic intervention (e.g., polypectomy), only the appropriate therapeutic colonoscopy CPT code should be reported. The diagnostic component is considered inherent to the therapeutic procedure.
  • If a screening colonoscopy (Medicare G0121 or G0105, or CPT 45378 with appropriate screening diagnosis for commercial payers) identifies a lesion and only a biopsy is performed without removal, CPT 45378 should be reported with a diagnostic ICD-10 code for the finding, and potentially modifier 33 (Preventive Services) to indicate the screening intent if applicable by payer.
  • If the colonoscopy is incomplete (e.g., unable to reach the splenic flexure due to patient intolerance or anatomical obstruction), modifier 52 (Reduced Services) should be appended, and documentation must support the reason for incompleteness and the extent of the examination.
  • Documentation must clearly state the indication for the procedure, the extent of the examination (e.g., to the cecum), all findings, any specimens collected, and patient tolerance to anesthesia and the procedure.
  • CPT 45378 has a 0-day global period.
  • For Medicare beneficiaries, routine screening colonoscopies are typically reported with G0121 (high-risk) or G0105 (average-risk). If a lesion is found during a screening colonoscopy and only biopsied (not removed), 45378 would be reported with the appropriate diagnostic ICD-10 code and possibly modifier 33 or PT, depending on Medicare rules, to ensure the screening benefit is applied.

Associated ICD-10 Codes